Cord-circuit for telephone systems.



-B. n. WILLIS. com) c'mun FOR TELEPHONE SYSTEMS.

APPLICATION FILED OCT- 4 191i,

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APPLICATIN FILED OCT. 4.1911.y

Patented ont 12, 1915.

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B. D. wI'LLIs. CORD CIRCUII]F FOR TELEPHONE SYSTEMS.

I, APPLICATION FILED IJI:T.4` IIIII. 1,156,450. l

. Patented 0pt. 12, 1915.

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UNITED sTATEs PATENT oFrIcir.

BERNARD D. WILLIS, .0F CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CORD-CIRCUIT FOR TELEPHONE SYSTEMS.

To all cham it may concern.'

Be itknown that I, BERNARD D. WILLIS, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented `a certain new and'useful Improvement in Cord-Circuits for Telephone Systems, of which the following is a specilication.

Aio

My invention relates to telephone systems, and more particularly to an improved cord circuit for use in the saine.

My improved cord circuit is especially adapted for use in connection with semiautomatic telephone systems, and is what I terIn a universal cord circuit in that it may be used to connect with magneto or local battery manual lines.` coinnion battery manual lines, or with trunk lines leading to and from an automatic exchange. Usually, when a cord circuit is connected with different types of lines in this manner, difficulty is encountered in obtaining proper supervision owing to the fact that different supervisory circuits are required when connection is made with a local battery line than those which are required for a common battery line. AIn my improved cord circuit the 'supervisory circuits yare automatically adapt'- ed, upon insertion of the plug into the Jack, to the particular line with which connection is made.

A further feature of'novelty is the provision of a cord circuit which is adapted for use in both local and common battery manual lines, and with an automatic system in which supervision is obtained by reversing the battery upon the line when the called subscriber answers.

A further object of novelty is in the improved method of obtaining supervision from local battery magneto lines, whether these lines are in-a manual system or in a semi-automatic system. Ordinarily, the cords for use with magneto lines are provided with a single relay in each end of the cord. This relay has two windings, one of which is bridged across the cord and the other of which is adapted to be included in `a locking circuit including a pair of nornially' open springs controlled -by its own armature and the third conductor of the plug and jack. lVhen the subscriber rings olf, the relay is energized by magneto curl Specication of Letters Patent.

Application filed October 4, 1911. Serial No. 652,754.

Patented oct. 12, 1915.

ing winding, and likewise closes the circuit of the disconnect signal. The magneto ciirrent being alternating in character, and the current in the locking winding being direct, if the last impulse of the magneto current happens to be in the direction to oppose the current in the'locking winding, there would no disconnect signal given. In my improved cord circuit I obviate this objectionable feature bythe use of two relays, one bridged across the cord and one in the third 'con-l ductor, said second relay being normally shoi't-circuited through the springs of the iist relay as well as through a pair of its own springs.l When the bridged relay is energized by the magneto current, it opens the short-circuit of the other relay, which immediately energizes and opens its shortcircuit at another point. The second relay cannot then `.be disturbed by any furthero'perations of the bridged relay, and is, therefore certain to` remainlenergized to keep the circuit of the disconnected signal closed.

These and other objects of my-invention will be more readily understood by reference v ofv a telephone system embodying theprinciples of my invention. Fig. 2 is a diagrammatic representation of a common battery manual line A4, a local battery manual line A3 'and a manual switchboard operators cord circuit C. Figs. 3 and -t are views representing automatic switching apparatus arid substations.

In Fig. l, M represents a portion of a manual switchboard to which are connected local battery manual lines A3, commonbttttery lines A4 and trunklines leadingto and from an automaticexchange D. Thefexchange D is of the so-called two-winef-typfe,,` z'. e., ofthe type in which the central'oiee apparatus is controlled over the two sides of.

` the'calling line in series. Referring tothe exchange D', each of the substatioiisAfis line switches has common access to a number of first selector switches E. The selectors E have access to a number of trunk lines, some of which lead tov connector switches F, while others lead to jacksfj" on the manual board M. From the jacks j on the manual board M trunk lines lead to "se-"1165"- lectorv switches E which have access tothe same. trunks asthe selectors E. Of course, the exchange may comprise a number of `groups of 'substations such as herein shown,

' -switch F at the automatic exchange D.

` Fig. 4 is a representation oil-'one of the substations A of the exchange D', together with its line switch I', a master switch N', a selector E and a jack j at the manual board M. l

in the various drawings there are shown a number of batteries B, having yone terminalgrounded, for operating the switching apparatus, relays, signals, etc. ,There are also shown a number of ringing current generators .S and busy signalingzmachine's T. Any number of batteries, ringing current generators and busy signaling machines may be used, but generally one of each in each oiice is found to be a satisfactory arrangement l if-'The' common battery manual substation A4 (Fig..2) may be of any.. suitable type,

and, as herein shown, comprises the usual` receiver 2, switch hook 3, transmitter 4,

.ringer 5, induction coil 6 and condenser 7.

gAt the central otlice the line conductors 8 vand 9 are connected to an answering jack j* and one or more multiple jacks js. At the central ofiice there is also allotted to the line the usual line relay 10`7 cut-oit' relay 12 and line lamp 13.

l circuit.

f The local battery substation A3, as hereinrepresented, comprises a receiver 14, switch hook 15, transmitter 16, local battery 17, Iinduction coil 18, condenser 19,'

magneto 'generator 2O and a ringer 21. At the central office there is allotted to the line conductors 22 and 23 an answering jack j, one or more multipleJ jacks jl, a line relay 24, a cutoil` relay 25 and a signal lamp 26.

` 'The operators cord circuit is similar in general respects to the usual cord circuits used in manual switchboard practice. Among other details it comprises two plugs p and p2 connected together through the condensers 29 and 30. A listening key K is provided by means of which the operator may connect her ytalking set with the cord Each end ofthecord is provided with a ringing key and a. calling device key.

I Since this cord is to be used for extending inafter described.

each controlled by a pair of relays, as here- As the supervisory circuits of each end of the cord are similar, only the answering end Vwill be referred to at this time. rl`he relay 34- is a polarized relay, having a pair of energizing windings, whose armature is pivoted in the center and may be attracted in either direction, depending upon the direction of the current in the windings. The armature returns to its midposition whei'iever-Hm relay is denergized. The 'connection between the windings of the relay 34 is controlled by the relay in such a manner that the two windings may be connected directly together in a bridge of the cord circuit, or may have the battery B con nected between them. The relay- 33 comprises two windings permanently connected toffether -with a lead runnin@ off from the junction point, which lead isadapted to be connected to ground by the operation of the listening key K. The left-hand winding of the relay 3,3 comprises comparatively few turns and has a rather low resistance and is connected with the sleeve of the plug p. The right-hand winding of this relay comprises a larger number of turns and is more sensitive than the left-hand winding.

The selector switches E5 (Fig. 3)and E (Fig. 4) are of the generaltype disclosed in United States Letters Patent No. 815.321, granted March 13, 1906, to Keith, Erickson and Erickson, being modified somewhat in order to operate in a two-wire system, z'. c., a system in which the automatic switches are controlled over the two sides of the line in series, in the manner shown in British patent to S. G. S. Dicker No. 129S of 1910.V

- leasing the switch are provided in the release magnet 51, which magnet releases the switch immediately upon energizing. As long as the switch shaft is in its lowest position, an arm 52 on said shaft disconnects `the magnet 51 from the battery by separating the springs and 54. The opera-.tion of the switch is controlled by the operator through the medium of the double-wound line relay 89. The selector likewise includes the relays 90, 91 and 92. which are slow act' ing, for a purpose which will be 'more cleanlv understood b v reference tothe complete operation of the system which follows. l

The conrector F (Fig. 3) is of the general type of connector switches disclosed in United States' Letters Patent 815,176, granted March 13, 1906, to Keith, Erickson and Erickson, but, like the selectors, is modified to '.pperate a two-wire system, as lfliWn-m said' British Patent No. 1298 of 0. Y As herein represented, the automatic substation A (F ig. 4) comprises the usual receiver 56,- receiver hook 57, transmitter 58, ringer 59 and condenser 60. In addition, the substation is provided with an impulse wheel 61 secured to a shaft 62 to which there is also attached a dialfnot shown) which is provided with Enger holes. The impulse wheel 61 carries upon its periphery a num- 'ber of impulse teeth 68 which are so arranged that, as the dial and impulse wheel return to normal position after having been rotated 'forward by the calling subscriber, each tooth that passes th'e cani 61 momentarily forces the spring 65 out of engagement with the spring 66. The dial and impulse wheel are returned to normal position r by `a spring (not shown).

The individual switch I is of the general type disclosed in British patent' to R. 1V. James No. 26,301 of 1906, and in the Amer can Telephone Journal of New York, N. Y., of June 6, 1908, being of a. somewhat moditied construction, however. Among other details vthe switch l' comprises a plunger (notshown) attached to the plunger arm 96 which is controlled by the magnet 97.v The magnet 97 has four energizing windings, namely, a pull-in winding 98, a cut-oli' winding 99, a line winding 100 and an auxiliary winding 101. The magnetic circuit 'of the windings 98 and 99 is separate from that of the windings 100 and 101, whereby the energization of theI windings upon one end ofl the magnet does not affect the armatures upon the other end. The winding 98 will operate both the armature 102 and the plunger arm 96, while the winding 99 is strong enough to operate only the armature 102. 1f, however, the winding 99 is energized while the plunger arm is in its attracted position, said arm may beheld inthis position by the winding 99 alone.

The master switch N is similar to the master switch shown and described in British Patent No. 1428 of 1910. Among its essential details it comprises a motor mag- Vnet 7llfor operating the ratchet wheel 75. The ratchet'wheel 7 5 is connected with a so called plunger shaft (not shown) in such a manner that a continuous rotary motion of said wheel gives to said shaft an oscillating motion to move the idle yplungers back and I forth in front of their trunk terminals. Se-

cured to the plunger shaft there is also a locking plate 178 having in its surface a number of, circular openings which are adaptedv to be engaged by the pin 177 on thearmature' 169. The openings in the plate 20. `energizes the relay 2e, which operates to 178 are so spaced that the pin 177 can engage one of them only when the plungers that are in engagement with the plunger shaft are directly in front of the terminal of a trunk line. The master switch N is also provided with a bank of contacts comprising the common segment 76 and one individual segment a for each trunk line. The

wiper 77 isadapted to' always keep the common segment 76 in electrical connection with the segment a which corresponds to the trunk line before the terminals of which the idle plungers are being held by the master switch.

The operation of the system is as follows: Concerning first the local battery or magneto substation, the operator vis signaledv close a circuit through the lamp-26 and a locking circuit for itself through the winding 110. The relay 21 thus remains lockedl and the lamp 26 continues toglow until the call is answered. The operator answers the call by inserting the plug j); into the 'jack i3 of the calling line. The engagement of the sleeve conduct-ors of the plug p and the jack completes a circuit extending from A ground G2 through the closed springs 113 of the relay 31, armature 115 and its back contact, left-hand. winding of the relay 38, plug p and jack and through the cut-off relay 25 to the battery B. The cut-olf relay 25 of the local battery lines has a comparatively high resistance, so that although it is energizedl over this circuit it does not permit sufficient current to flow through the left hand winding of the relay 33 to operatively energize it. ll`he energization of the relay 25 opens the bridge across the calling line through the winding 109- of the relay 24, and breaks the circuit through the winding 110 and the lamp 26. The subscribers lines and 23 are now connected with the tip and ring strands of the cord C, respectively, Y

desired. Connection can then be extended to any other line, as will hereinafter be eX` plained.

The subscriber at substation A3 has control of the supervisory lamp 3.2 at the corel C through the medium of tie, relays 31 and 33, The two windings ot' the relai' 31 are ,connected in series across the cord, 'One end of the rahtfhand winding of the relay 33 is connected to ground direct, while the other end ot said, winding connected to battery through the cut-ott relay and to ground through its own' armature 115 and the normally closed contacts of the relay The right-hand winding of the relay, 33 is, they@ fore` normally shortcircuited. lVhen the subscriber at vsubstation A" rings oit' upon the termination of the conversation, the re-' lay 3l will actuated by the ringing cur= rent from the substation magneto generator As soon as. the relay 34 operates to Open the springs 113, the short-circuit is remoyed from the right-hand winding of the relay 33, allowing it to energize in series with the relay 25,' The attraction of the armature .115 by the, enere'ization of the right-hund winding of the relai' opens the Short- Clrt'uitfat a second point. so'that said relay 33 remains energized after the springs 0105 again. T he engagement of the armature 115 with its .front Contact closes a circuit through the lamp 32. said circuit extending from ground (i: through the springs .113. armature 115 and lamp 32 to battery B. IVhen th@ relay 33 energizes it will be seen that the battQrVB inserted between the windings ot' thex relay 3l. but' this is without function at this time. In fact. as far as its operation 1n connection with magneto lines is con* cerned. it will be eyident that the relay 31 could be simply a single-wound non-polarized relay connected permanently across the cord circuit. It will also be evident that in so far as the operations just described are concerned, the left-hand'winding of the relay 33 is functionless. The relay 33 will remain energized and maintain the circuit of the lamp until the plug p is removed.

The abovel is the operation of the falling end of the cord C when a magneto substation Such as the substation A3 is the calling substation. and is entirely independent of the character of the line to which the connection is extended by the calling plug pi. In fact the supervisory circuits of the twoy eds of the cord are entirely independent each other. so that a description of the operation of either the calling or answering` end is true regardless of the character of the line 'with which the other, end of said cord is connected.

"hen the substation A3 is the called substation. the callingplug j# will be inserted in the jack j", and the substation A3 will be signaled by throwing the key K to force the springs 131 and 132 into engagement with the springs 133 and 131, respectively, whereby the calling and called lines are disconnected and the generator S bridged across the called line, After the 'conversation completed the operator may he given a disconnect signal by the operation of the generator 2O in much the same manner as when the substation A3 is the calling substation. In this case the current from the generator 20 flows through the relay 129 in thel calling end of the cord. The relay 12S) being in all respects the same as the relay 3l operates to remove a short-circuit from the leftrhand winding of the relay 130, which like the relay 33 viu the other end of the cord. The relayi130 operates t0 Close a circuit through the 12111111121 the same manner in which the relay 38, closes u circuit through the lamp When a .common hatteryeubstaton A* is the calling substation, the operator is sfig-V naled simply by theremoval of the receiver from the switch hook. 'The engagement' of the switch hook 3 with the contact point 133 completes a circuit extending from ground G5 through the winding 124 of the relay 10, armature 135, line 8, switch hook 3. contact point 133, primary winding of the induction coil 6, transmitter 4, line 9,

armature 13S and winding 139 to battery The relay 10, upon energizing. closes aeirf cuit through the lamp 13. 'hen the operator inserts the plug 72 into the jack j* in answer to the signal displayed by 'the lamp 13. the calling line is extended to the tip and ring strands of the cord C- and an energizing circuit is closed through the lefthand winding of the relay 33 of the cord and through the cut-off relay l2 of the line A4. This circuit extends from ,ground G2. through the springs 113 and 115, le'ft-haI 1d-`E winding of the relay 33, sleeve of the Iplu-g p and jack j* and through the relay 12to battery B. The relay 12 has a lower resistance than the cut-oit relay 25 of the local battery line A3, so that in this instance the relay 33 is energized through its lefthand winding. The relay 12, upon energizing, disconnects the relay 10 from the line. which relay then denergizes to break the circuit of the lamp 13. The energization of the relay 33 serres, through the medium of its armatures 117 and 118, to connect one winding of the relay 34 to ground and the other winding to the non-grounded pole of the battery, thereby providing the calling substation with talking current over a circut extending from ground Gr6 through the armature 117, the right-hand winding left-hand winding of the relay 34 and arma.-

ture 11S to battery B. The relay v34 is energized by this current in the proper direc tion to separate the springs 113, thereby preventing the closureof the circuit of the lamp the switch hook at the time the by the engagement of the armature 115 with its front contact upon the energization of the relay 3i". When the receiver at the substation A4 is restored to the switch hook upon the termination ot the conversation, the energizing circuit of the relay 3l is destroyed, allowing the springs 11? to close. The engagement ot these springs completes n ciitlllt through the lalnp 32. This circuit extends from ground G2 through the springs 11?). armature 11T and its front contact. and lamp P2 to battery B.' When the plug /i reinoyed. the' relays 12 and 3?, deenergize. restorii'ig' the culling line and answering end ot' the cord to normal position. 1t the coinnion buttery substation A* is a called substation, the calling plug is then inserted into one of the multiple jacks jl. The engagement ot' the sleeve contacts of the. plug' /F und jack ,is completes a circuit from ground Gtthrough the springs 119. arnrature 126. right-hand winding of the rel: 130 and through the relay 12 to buttery. s has been explained, the relay 130 is sinii lar to the relay 33 in the other end of the cord. and controls circuits which aresimilar to the circuits controlled bythe latter relay. rl'heret'ore. the energization ot' the relay 130 serves to connect the ring strand of the calling end of the cord vto ground through one winding of the relay 129, and to connect the tip strand to 'battery through the other winding of the same relay. Since the receiver at the lcalled substation is on plug is insei-ted. the relay 1'29 is not energized immediately. (.`onse(|ue1itl the energization of the relayli) also closes a circuit through the 'lamp 121. This circuit extends from groundaGJE through the springs 119 ot the relay 129. arn'iature 1'20 and its front contact and lamp 121 to battery B. The operator signals the ctuninon batterysubstation in the saine manner as the local battery substation is signaled--tl'iat is, by operating the key K. to bridge the generator S across the line. ll'hen the called suliscriber removes his receiver. a bridge is closed across the line through the secondary circuit ot the sul'istation. rllhe relay 1'29 at the cord thereupon energizes in the proper direction to separate the springs 119. The separation of thesel springs destroys the circuit of the lamp 1'21. The extinguishing of the lamp signifies to the operator that the called subscriber has answered. Then vthe receiver at the called substation is again restored to the hook. the relay1 lighting the lamp 121, thus giving the operator a front disconnect signal-that is, a disconnect signal in the calling end of the cord. Then a connection is desired ,with one of the automatic substations of the automatic exchange D (substation A. shown in Fig.

129 .denergizes again,

l. for instlancel, the plug p2 is inserted into the jack (Fig. 3). The sleeve conductors ot' the jacks of the trunks leading to the automatic exchange'haye no (bonnet-tion to battery. sothat no circgit is closed through 'the right-hand winding"`ot` the relav lL5() at this time. The engagement of thetip and ring conductor." off-the plug p2 and jack j connects the cord C with a selector switch 15, through which latter connection with any line in the exchange D may be 0btained. The operator now operates the key K2 to torce the springs 162'and 161'into engagement with the springs 161 and 163, respectively. whereby the automatic calling device is bridged acrossthe trunk line. A circuit is thus completed from `ground G (Fig. 3)v through the lower winding of the selector line relay 89, side switch wiper 17, tip springs of the jack 3'5 and plugv 792, springs 162 and 161 of the key K2, calling deyice springs 27 and 28, key springs 163 and lol, ring of the plug p2, ring spring of thejack j, side switch wiper 16 and upper 'winding of the relay S9 to the battery lead 165. The relay 89, upon energizing, oper- -ates to shift the spring 166 out of engagement with the spring 167 and into contact with the spring 168, whereby a circuit is closed through the slowvacting relay 90. This circuit extends from ground G8 through the springs 166 and 16S and relay 90 t0 the` battery lead 165. The relay 90, upon energizing. operates to extend a connection from the spring 167`through the relay 9'1 tothe vertical magnet 41. Assuming the number of the substation A to be 220, the operator now operates the calling device to separate the springs 97 and 28 momentarily twice to operate the selector E5. Each time the springs '2T and '2S are separated the selector line relay 89 denergizes momentarily, completing a circuit 'through the vertical magnet il. This circuit extends from ground G8 through the springs 170, relay 91, magnet 1l and side switch wiper 1S to the battery lead 165. The yertical magnet il receives two impulses over this circuit. operating to raise the Wipers 41, 42 and 13 two steps opposite the second row or leyel of bank contacts. The relay 91 being slow acting does not have time to cleenergize during the momentary interruptions of its circuit by the relay 89 during the above operation. The relay 91, which is included in the energizing circuit of 'the yertical magnet, is energized bythe irst impulse, and being low acting reninains in its energized positin'fguntil' after the last impulse has been deliyered totlievertical magnet. 1n its energized position the relay l91 operates to complete,A al circuit from ground GrS through the` springsl'lt an@ '172 and theV private magnet.-

tof thefbattery lead 165. When thezre'laj QL-'dehergize 166 and 167, 169 and' thereupon denergizes andI allows the side .switch to pass lto second position.'

The movement of the side switch wiper 48 from first to second-position disconnects battery from the vertical magnet 44, and com`letes a circuit through the rotary magnet 45. This circuit extends from 'ground Grg through the interrupter-springs 173, rotary magnet 45, slow acting relay 92 and side switch wiper 48 to the batterylead 165. The rotary magnet energizes upon the closure of this circuit and operates to rotate the wipers 41 42 and 43 one step, force down the private magnet armature and to open -its own circuit at the interrupter springs 173. The

' rotar 'magnet thereu )on dener izes and if the first trunk of the second level is idle, allows the private magnet armature to tall back, causing the side switch' to pass to thirdy position. If thel first trunk is busy, however, the private wiper 43 finds the first contact guarded by a' ground potential, thereby completing a locking circuit for the private magnet 50. This circuit extends from the grounded bank contact through the wiper 43, side switch wiper 49 (in second position) and the magnet 50 to the battery lead 165. This locking circuit prevents the Side switch from passing to third position. As long as the side-switch remains in second position the rotary magnet 45 continues to operate in a manner similar to that of a buzzer to rotate the wipers 41, 42 and 43 past the busy trunks. i y

As soon as the wiper 43 passes onto the non-grounded contact of an idle trunk, the private magnet 50 denergizes and the side switch passes to third position.. The disengagement of the wiper 48 with its secondposition contact point breaks the operating circuit of the rotary magnet 45. The relay 92.` which is included in the `operating circuitof t-he rotary magnet, is slow acting and consequently remains energized for an instant after the wipers are rotated the last step. Consequently, at the instant the side switchpasses to third position the seized trunk'is provided with a guardingr` potential fro'm ground G10 through the springs 174 and 175. contact point 176, side switch wiper 49 and private wiper 43 tothe selector private bank contacts of ,the trunk line leading to the connector F. The engagevrment of thesideswitch wipers 46 and 47 with their third-position cont-act pointseX- tends the connection from the cord C to the connector F through the shaft wipers 41 and 42. The relay 178 is thereupon energized by a ,iow of'current from ground G11 throughfthe lower winding of said relay, through the springs 179 and 180, contact 181, wiper 42., thence through the cord C and back over the other side of the line, ...through the wiper 41, bank contact 182, springs 383 and 384 and through the upper winding of the relay 17 8to the battery lead v 165. The relay 178, upon energizing, operates to close the circuit of the relay l183. The relay 183, upon energizing, operates to place a new guarding potential on'the private bank contact ,184 to guard the trunk after the relay 92 denergizes. This new pot\e'ntial extends from ground G12 through the side `switch wiper 185. springs 187 and 186 to the contact 184. Also, as soon as the relay 92 of the selector E5 denergizes, the relhy 90 is provided with a new circuit extending from ground G12 to the contact 184, as just traced. through the wiper 43, side switch wiper 49. springs 175 and 188 of the relay 92 and relay 90 to battery;v This circuit is closed before the relay 90 has time to denergize after its former circuit is broken by the denergization of the relay 89 when the side switch passes to tdiird position. The relay 92 is quicker in its action than the relay 90."and its only function is to `provide a guarding potential for the seized trunk` until the relay 183 of the connector has time y to energize. v

.The operation of the operators calling device for the second digit 2 breaks the circuit of the connector line relay 178 twice. Each time the relay 17 8 denergizes, a circuit is closed through the vertical magnet 189. This circuit extends from ground G1 through the springs 190 and 191,193 and 192 of the relay183 (which remains energized while the impulses are being. delivered). relay 194, vertical magnet "189 andj side switch wiper 195l to the. battery lead 165. The magnet 189 operates to raise the shaft wipers two steps. The slow acting re-l lay 194 is energized by the first impulse to the vertical magnet, and closes a circuit from ground (l13 through the springs 196 and 197 'and' private magnet 198 to the battery lead'165. The relay 194 remains in its operated position until after the last impulse is delivered tothe vertical magnet, whereupon it denergizes, breaking the circuit of the private magnet'198, which then permitsthe side switch to pass to second po'- Tsition. Now, when the relay 178 dener- .gizes in response to the operation of the 4 operator-s calling device for the last digit 0, it closes a circuit through the rotarymagnet 199. This circuit extends from ground G15 through the springs 190 and A 191, 193 and-'192, relay 194, springs 201 and 202, rotary. magnet 199 and side switch.-` wiper 195 to battery. The rotary magnet receives ten impulses overthis circuit, operating to rotate the wipers onto the contacts of the desired line. The slow acting relay operates to close the circuit of the private magnet while these impulses are being delivered. just as in the case ot' the previous digit. When the relaiv 191 deinergizes at'ter the last impulse is delivered. the private magnet 19S delin'ergizes also. it the called line is idle. and permits the side switch to pass to third position. The engagement of the side switch wipers 2023 and 20l'uith their third-position contact points extends the line connection through the wipers 205 and 201i. contacts 20S and 2051 and'theconductors 211 and 212 to the called line (Fig. l). The engagement of its third-position contact point hv the side switch iviper 21-1 extends a guarding potential to the conneclor private bank contactsl of the called line. and provides an energizing circuit .for the eut-oli' Winding ill) of the line switch I. 'l'liisA circuit extends from ground G16 through the side switch Wiper 21l'to the private wiper 20T and contact 210. and thence to the corresponding contact in the banks' oi. all connectors which have access to the line From the contact 210 the 1-ircuit also extends over the conductor 213 and through the winding 99 of the switch I lo the batterv lead 215. The ivvinding fill. upon energizing. attracts the armature 102. which operates to disconnect the ground G17 and the line Winding 100 from the called line. and to connect the conductor 211 with the line 216.

When the connector side switch Wiper 195 rezenhes third position. the ringer relav` 21S beginsA to be intermittently energized over a circuit extending from ground G13 through the interrupter 219. relayy 21S. springs 220 and 221 and'side switch wiper 195 to the batterv lead 103. Each time the relaiv 218 is energized it operates to disconnect the calling and called lines. and to Ybridge the generator S across the calledfline to ring the bells .35).

After the operator atthe cord C (Fig. 2l hascompleted the call` the kev K2 is restored to normal position. therebv cutting off the calling device and substituting therefor a bridge consisting' of the relav 129. rThis relav is thus included in the energizing circuit of the connector line relav 17S. andthe current is in such a direction as to attract the armature in the proper direction to close the springs4 12.1.therebiv closing a circuit through the' lamp 121.

'hen the called subscriber removes his receiver in ans-wer to the call. the circuit of the ringer 5f opened and the talking circuit is bridged across the line. The first time the ringer relav L11q ot the connector ileincrgizesl after this occurs. the called substation provided With talking current over a circuit extending from ground G21 through tiie right-hand uintliug of the relav Wingsv 22V and 22T ot' the private magnet 19e. ringer relav springs 22S and 229. side switch wiper 20-1. shaft wiper 206, Contact `of a circuit through the rela;v 23S.

216,'springs 2132 and v233. conductor 211. convtact 20S. wiper 207i. side'siritch lu'iper 2031 ringer rela'v springs 231 and 2515. springs 236 and 23T and left-hand winding of the relav 223 to the battery lead 1(35. .Therelay 225 is energized hv this current. and b v shitting the springs 1Q() and 383 reverses the line connections ot' the relav 17S. thereh)v re; versing the direction of the flow of the current in the trunk line leading from the miur ual to the automatic oiiice. This reversal of the current causes the polarized relai1 129 at the cord to attract its armature in the opposite direction to open the springs 125 and therebv extinguish the lamp 121. which informs the operator that the called subscriber has answered.

Another result of the energization ot the connector hack bridge relav 22.3 is the closure This circuit eXtends from ground G15 through the springs 190 and 239 of the line rlelav 17S. springs 210 and 211 ofthe rela)v 225 and relav 23S to battery. The rela'v 23S. upon energizing. breaks the circuit ot' the ringer rela v 21S at the springs 221 and 220. and forms a locking circuit for itself b v the closure of the springs 2li-3 and 211 so as to prevent the circuit of the relav 218 from being again energized when the called subscriber hangs up his receiver and allows the relav to deenergize.

The hanging up ot the receiver at the called substation breaks the energizing circuit of the connector hack bridge relav 225. causing it to denergize. which again reverses the current in the relav 129 at the.

operators cord. This reversalot' the current causes the armature of the relav1f129 to he again attracted in thedirection 'toclose the springs 125. thereb; lighting the lamp 121 to give the operator the disconnect signal.

The release ot' the selector E5 and connector 1" is brought about b v the removal otl the plug p: from the jack The removal ot' this plug breaks the energizing circuits ot' the connector line relav 17S and the rela'v 129 at the cord. The denergization ot' the relav at the cord extinguishes the lamp 121, The decnergization ot' the connector line relav 17S breaks the circuit of the release relav 1S3 and that ot the selector release relav 90. since its circuit is controlled hv the 1ela}v 17S after the side sivitch iviper 185 reaches third position.

ergizing circuits ofthe release magnets of their respective switches. The circuit of the release fnagnet 21V of the connector F extends from ground G15 through the springs 101') and 15,11. lll?) and 219. magnet 216 and springs 21T and 21SV to the batteriv The de'e'nergization of the relays 183 and 90 closes the enlead 165. The release circuit vof the .selector E5 extends from ground Y.Grthrough the springs 166 and 167 169 and;250, magnet'l and springs and 53't0 the battery lead 165. The energization of the magnets 216 and 51 causes the mechanism of their respectiwe switches to be restored to normal position. The circuitsof the magnets 216 and 51 are opened at the springs 247 and 248 and 54 and 53 whe11`ltl1e'sl1afts of the -respective switches reach their lowestposiline is busy the private wiper 207 iinds the contact 210 guarded by a ground potential which completes, a circuit through said wiper 207, side switchwiper 211 in second position) and the lower winding of the "relay 251 to battery. "(If therelay 251 is thus energized when the relay 194e denergizes, the side switch cannot pass from second position becausel the private magnet remains locked over a-circuit extending from ground' G12 through the side switch wiper 185, springs 187 and'186, and upper winding of the re ay 251 and private magnet 198. The locking ,of the side switch prevents the completi n of connection with the called line, while the engagement of the springs' 251 and -255 on the relay 251 connectsthe busy signaling machine T with the calling line. A busy signaling curren-t then flows Afrom the batteri7 lead 165 through the secondary ofthe induction coil, through the springs and 251, side v.switch wiper 204, ringer relay springs 229-and 228, thence over-the talking circuit represented by the heavy conductors to and through the cord C to the calling substation and back over the other side of the line and through the ture 108, which operates -to close a' circuit from ground' G17 through the springs 279 and 281, windings 98 and.101 of the magnet 101, Contact point 168 and armature 169 to the battery lead 215. The winding 98, upon energizing, attracts the plunger arm 96 and cut-off armature 102. The armature 102 operates to disconnect the ground G17 and winding 10Q `from the calling line. The armature 103 does not fall back immediately whenl the circuit of the winding 100 is broken, but iremains held up by the currentin the winding 101 until said winding is short-circuited at'. the springs 285 and 286 by the plun'ger arm 96. lVhen 'this occurs the winding 101 denergizes slowly. and after an instant allows the armature 103 to fall back to V,break the circuit of the pull-in winding 98. By the slow action of the winding 101 the falling back of the armature 103 is delayed long enough to pe mit a circuit to be clbsed'through the winding 99 before the circuit of the winding 98 i's broken.

upper windingof the connector line relay 178 to the battery lead 165 and thence to the nto engagement by the plunger of the lie induction coil 256.

lVhen one of the automatic subscribers,

vthe subscriber at substation A (Fig. 4) t for instance, wishes to make a call through the manual board, the operatoris signaled asA follows: WVhen the receiverv at substation A is removed from the hook, a circuit is closed through the line winding 100 of the line switch I. y This circuit extends from ground G17 through the springs 279 and 280, line 217 ,shook switch springs 230 and 231, impulse springs 66 and 65,1'eceiver 56, transmitter 58, line 216, springs 232 and 282 and winding 100-to the battery lead 215. The winding 100 thereupon attracts the arma- The circuit through the winding 99v is closed as follows: lVhen the plunger arm is attracted. the line conductors 216 and 217 are extendedito the selector Eitlirough the switch wiper 296. thence over the heavy conductors to and through the substation A. and backover theother side of the line and through the side switch wiper 297 and the upper winding of the relay 295 to the battery lead 215. The relay 295., upon energizing, operates to close a circuit from ground G2? lthroughgthe springs 298 and 299 and relay 300 tothe battery leadV 215. The-relay 300, upon energizing, completes a circuit from ground G27 through the springs 301 and 302, 292 and 291 and winding 99 of the magnet 104 yto t-he battery lead 215. The current inthis winding serves to hold the plunger arm 96 and armature 102 in their 'operated' positions after the winding 98 is denergi'zed.

lVhen the springs 293 and 294 are forced switch I', a circuit is closed through the relay 172 of the master switch N4 This c'r- `Acuitl extends'from ground G28 through t e l 'springs 293y and 294, master switch bahk he contact 175. wiper 77 and relay 172 to battery lead 215. The relay 172, vupon enf.

ergizing operates to close a circuit through the rela,T 176. The relay 176, upon energizing. operates to withdraw the pin 177 125 Since this circuit includes the interrnpter Y assenso springs 180, the magnet` 74: continues to operate in a manner similar to that ot a buzzer as long as the armature 169 engages the contact point 179. The ratchet wheel 75 is thus given a continued rotary motion to move the plunger shaft andwall idle plungers that are in engagement therewith away from the trunk just seized toward an idle one. After the plunger moved a short distance, the wiper 77 passes oli' the contact 175, allowing the relays 172 and 176 to be denergized. rl`he armature 109 cannot fall back after the relay 170 is denergized until the nextI opening in the plate 17 8 passes under the pin 177, thus preventing the master switch from stopping until the idle plungers have reached a position directly in front of the terminals ot a trunk line. lf the next trunk line after the one seized by the switch I had been busy, the wiper 17 5 would have found the corresponding contact grounded, the relays I172 and 170 would have remained energized while the next opening in the plate 17 8 was passing under the, pin 177, and consequently the plungers would have been carried past the busy trunk to an idle one.

Now, when the subscriber at substation A. operates his calling dial for the digit corresponding to the bank level of the selector E, to which are connected the trunk lines leading to the manual board, the selector E operates in the same manner as explained for the selector E5 to bring the wipers 303, 301 and 305 into engagement with the contacts 306, 307 and 308 of an idle trunk line leading to a jack j through the condensers 300 and i310. Then the side switch ot' the, selector l passes to third position, the relay 295 is disconnected from the line and the relay 311 is substituted therefor. The relay 311, upon energizing, furnishes a guarding potential for the trunk line, and a holding circuit Jfor the release relay 300 of the selector E. This circuit extends from ground G29 through the armature 312, contact point B13, contact 307 .and the corresponding Contact in the banks of all selectors which have access to this trunk line, and also over the wiper 304, side switch wiper 814, springs 416 the relay 300 to the battery lead 215.

The engagement of the armature 315 with the Contact pointfl upon the energization of the relay 311 bridges the coil 317 across the end or' the trunk leading to the jack j. It will be seen that the jack j and relays associated therewith are exactly like the jack ,7'4 of the common battery manual line A4 (Fig. 2). Thus, when the coil 317 is bridged across the trunk it has the same effect as when the receiver at the substation A2 is removede-that' is, the line relay 318 energizes and lights the lamp 819. Theoperator thereupon inserts thefplug p into shaft has beenv lcommon battery lines,

and 415 and' through springs the jack j, whereupon the relays 33 and 34: operate in the same manner as when the plug y2 is inserted into the jack j4 of the line A4. When the receiver at the substation -A iS restored to the switch hook, the trunk relay 311 denergizes, breaking the holding circuit of the selector release relay 300 and opening the bridge across the trunk line through the coil 317. This permits the relay 34 at the cord C to denergize and close they circuit of the supervisory lamp 32 in the same manner as explained when the receiver at a calling common battery substa tion A4 is hung up.

The relay 300 at the selector E denerthe relay 311 and, upon denergizing, closes the circuit of the release magnet 320 and destroys the holding circuit of the Winding 00 of the line switch E. The selector E and the line switch l. are thus restored to normal position and left in readiness for another call. v

lt will thus be seen that I have devised an improved cord circuit which is automatically adapted for use inestablishing a connection between extending to an automatic exchange.

1While l have illustrated my invention in connection with a semi-automatic telephone system in which switches of a well-known type are employed, it will be understood that I do not wish to limit my invention to such a system, as my improved cord circuit is equally as well adap ed to be used in connection with any known automatic switches,

local battery manual lines,

or with trunk lines or may even be used in connection With an entirely manual system inl which, it is desired to establish a connection between local battery magnetoisubscribers, or between local battery magneto subscribers and com mon battery subscribers Other obvious uses and modiiicati'ons will readily suggest themselves to anyone skilled in the art, and l do not, the'efore, wish to limit myself to the exact con onction shown and described.

lVhat l claim asmy invention isz- 1. In a telephone system, a cord circuit, a relay bridged across the talking circuit, a second relay normally shortcircuited of the first-mentioned relay, means for momentarily energizing the irstmentioned relay to remove the short-circuit Jrrom the second relay, means for energizing the second relay when the shortcircuit is removed, means controlled by the second relay, when energized, to maintain the shortcircuit open, and a lamp adapted to be lightl.,

ized by the energization of the second relay. y

flrstmentioned relay, means controlled, by said second relay, when energized. `to maintain the. l'short-circuit open. and a supervisory signa controlled loe/said second relay.

3 "In a telephone system, a cord circuit. a threeconductor plug therefor, -a relay bridged across said cord circuit, a second relay connected to the sleeve ot said plug, a supervisory signal controlled by said second relay, andl a short-circuit-t'or said second relay controlled by said bridged relay.

4. In al telephone system, acord circuit. a relay bridged across said cord. a plug for said cord, a second relay connected to a contact of said plug, a normally closed shortcircuit for said second relay, means for opening said short-circuit upon energization of said bridged relay. and a supervisory sigbridged relay for opening said short-circuit` nal controlled by said second relay.

5.` In a telephone system, a cord circuit. a relay brldged across said cord, a second relay, a normally closed short-circuit about' said second relay, means controlled by said means controlled by said second relay for maintaining said short-circuit' open, and a supervisory slgnal controlled by said second relay.

6. In a telephone system, a plurality of subscribers lines, magnetos at the substa- '.from said magnetos, a second relay. a normally closed short-circilit for said second relay cont-rolled by said first mentioned re lay. and a supervisory signal controlled by said relays;

8. In a. telephone system, a plurality of subscribers lines, magnetos atthe substations thereon. a cord circuit adapted to be connected with ,said lines. a plug for said cord having a pair of talking contacts and a. third contact, a relay connected to said third contact. a normally closed short-cin cuit about said relay, a second relay bridged across said cord for controlling said shortcircuit. and a supervisory signal controlled by said first-mentioned relay.

9. In a telephone system. a plurality ot subscribers lines. magnetos at the substa- 'tions thereon. a cord circuit a'dapted to be connected with said lines. a plug' for said cord having a pair of talking contacts and a third contact. a relay connected to said third contact. a normally closed short-cir cuit about said relay, a second relay,bridged cord is inserted into a jack.

across said cord for controlling said short circuit, means controlled by said firstanentioned relay for maintaining said shox t-cir'- cuit o/pen when said first-mentioned relay is energized. and a supervisory signal controlledby said iirstanentioned relay.

1U. A telephone system including magneto manual lines. common battery manual lines and automatic lines, a. cord circuit for use in establishing a connection between any two of said lines, a supervisory signal for said cord, and means for controlling said signal by reversing the current upon the line when connection is established with an automatic line.

l1. A telephone system including manual and automatic lines, a cord circuit for use in extending a connection from a manual to an automatic line. a supervisory signal in said cord circuit, and means ltor controlling said signal by reversing the current u on the line when a called automatic subscrier answers.

1'2. A telephone system including automatic subscribers lines, a cord circuit for use in extending a connection to said lines, a relay bridged across said cord, means for reversing the current through said relay when the called subscriber answers, and a supervisory signal controlled by said relay.

1-3; .A telephone system including manual lines and automatic lines, a cord circuit for use in extending a connection between any two of said lines, a relay in said cord circuit, a supervisorysignal, and three. different methods b v which Vsaidl relay controls the operation of said supervisory signal, depending upon the character of the line with which said cord is connected.

1l. In a telephone system, local battery 105 and common battery manual lines and alltomatic lines, cut-off relays associated with said manual lines, a cord circuit for use in establishing a connection between any two of said lines, a. supervisory relay in said cord, a supervisory signal controlled by said relay.' means whereby the method of operation of said superyisory relay is dependent upon the resistance of said cut-off relay when connection is made with a manual line, a second relay in said cord, a second superyisory signal controlled by said second relay. and means whereby the operation of said second relay is dependent upon a reversal of current upon the line when connection is made with an automatic line.

15. In a telephone system, a cord circuit,

a double-wound polarized relay normally bridged across said "'cord circuit, a second relay provided with means for including a 12b battery in the bridge between the windings of said polarized relay, and means for energizing said second relay when a plug of the 16, In a telephone system, a subscribers means controlled by said line terminating in a jack, a cord circuit, adapted'to be connected with said line, a double-wound relay normally connected directly in bridge of said cord circuit, a second K ized relay connected in bridge of said cord,

a second relay, means for connecting said second relay in 'series with said cut-oill relay when said plug is inserted in said jack, means controlled by the energization of said second relay for including a battery between the windings of said polarized relay and in bridge of the cord circuit, and a supervisory si al controlled by said relays.

" 18. In a telephone system, a subscribers line, a cut-olf relay associated with said line, a cord circuit, a relay bridged across said cord circuit, a second relay normally shortcircuited through the springs of said firstmentionedrelay, means for energizing said second relay in series with said cut-off relay, second relay, when energized, to maintain the short-circuit open, and asupervisory signal controlled by said second relay.

19. In a telephone system, a subscriber-s line, a cut-off relay associated with said line, a second relay bridged across said cord circuit, a third relay having a. pair of energizing windings, a short-circuit for one of said windings normally closed through springs controlled by said second relay, circuit means for energizing said third relay in series with said cut-off relay, and circuit means controlled by the energization of said third relay', for opening said short-circuit and for including a battery in series with said'second'relay in bridge of the cord circuit.

2U. In a telephone system, common battery and local battery subscribers lines, cutoff relays of different resistaiices associated with the different types of lines, a cord eircuit for ilse in establishing connection between any two of said lines, a relay connected in bridge of said cord circuit, a second relay having a normally closed short-circuit about one of said energizing windings, means for including the other of said energizing windings in series with one of said cut-oit relays when connection is made between the cord and the line, means whereby the operation of said second relay, when so connected, depends -upon-the resistance of said cut-off relay, and

means controlled by the energizaftion of said -means for establishing a a pair of energizing windings,

automatic and manual second relay for including a battery in series with said first-mentioned relay in bridge of the cord.

:21. In a telephone system, automatic and manual subscribers lines, means for establishing la talking'circuit between any two of said lines, a supervisorysignal for supervising said connection, abattery adapted to be connected with said talking circuit, and mean-s for controlling said supervisory signal by reversing the connection of said battery to said talking circuit.

22. AIn a telephone system, a plurality of automatic and manual subscribers lines,

talking circuit between any two of said lines, a battery adapted to be bridged ac-ross said talking circuit,

a supervisory signal for supervising said connection, and means for controlling said supervisory signal by reversing the connection of said battery with said talking, circuit.

23. In a telephone system, a plurality of automatic and manual subscribers lines, means for establishinga talking circuit between any two of said subscribers lines, a supervisory signal for supervising said connection, a battery adapted to be bridged across said talking circuit, means for reversing the connection of said battery with said talking circuit upon theresponsept the called subscriber., and means for controlling said supervisory signal by said reversal of current.

24. In a telephone system, a plurality of automatic and manual subscribers" lines, means including a cord circuit for establishing a. talking circuit between any two of said lines, Va supervisory signal in said cord circuit, a battery adapted to be connected with said talkinhg circuit, and means for reversing the connection of said battery with v said circuit signal.

25. In a telephone system, a plurality of automatic and manual subscribers lines, means including a cord circuit for establishing a talking circuit between any two of to control said supervisory said lines, a supervisory signal in said cord,

and said automatic switch, a iupervisory signal in said cord, and means in said switch for producing a reversal of current for contro-lling said supervisory signal.

27. In a telephone system, a plurality of i subscribers lines, a

a plurality of cord circuit, an automatic switch fr tinding a alled subscribers line, a supervisory signz'il in said cord, a battery normally bridged across the talking conductors in.

a calling subscribers line, means including an automatic switch for extending a connect1on from said cord to the called line,A a supervisory signal m said cord, a battery normally bridged across the talking conductors in said switch, a relay 'tor controllmg said ctnnection, means for energizing said relay upon the. response of the calledsubscriber, means controlled by the energization of said relay for reversing thev connection ot said battery with the talking conductors, and means for controlling. said supervisory signal by said reversal ofcurrent.

29. In a telephone system, a plurality of subscribers lines, trunking means includmg a cord circuit for establishing a connection between two of said lines, a relay bridged across said cord, a third` conductor in said cord, a relay in said third conductor, said last mentioned relay being nor-V mally .short-circuited by said first mentioned relay, and a supervisory signal controlled by said two relays.

30. In a telephone system, local battery manual lines, common battery manual lines and automatic lines, a cord circuit t'or use in establishing connection between any two ot' said lines, a supervisory signal in said cord, and means for operating saidv ,nal by dit'- ferent kinds ot' current, depending upon the line \\'ith,which. said cord connected.

31. In/a telephone systenn local battery manual lines. common battery manual lines and automatic lines. a cord circuit for use in establishing connection between anytwo of said lines. 'a supervisory signal in said cord, and means for operating said signal by a momentary impulse ot alternating current, or from a common direct current source, or by a reversal of current, dependingy upon the line with whichsaid cord is connected.

32. In a telephone system, manual lines, local battery means for supplying talking current to certain of said lines. common battery means for supplying. talking current to vother of said lines, magnetos for certain of lsaid lines, automatic lines, a cord circuit provided with means adapting it ror use, in establishing a connection between any two of said lines, said cord circuit having supervisory signals operable by said magnetos and by the common battery.

33.. In a telephone system, a cord circuit,

a relay bridged across the talking circuit, a second relay normally short-circuited through springs of the Iirst-1nen'a ned relay, electrically controlled means for momentarily energizing the first-mentioned. relay to remove the short-circuit from the second relay. circuit means for energizing the second relay when the short-circuit is removed, automatic means controlled by the second relay, when energized, to maintain the short-v cuit open, and a lam!` dapted to be lighted by the energization t the second relay. f

3l. In a telephone system, a cord circuit, a relay bridged across said cord circuit, a second relay having a coil normally shortcircuited through the. Asprings of said first-1. mentionedrelay, automatic means comprising said second. relay whereby, when the second relay is energized, t-heshort-circuit is maintained open., and a" supervisory signal controlled by said second relay.

35. In a telephone system, a cord circuit, a relay bridged acrossfsaid cord, a plug for said cord, a second relay connected to a contact of said plug, a normally closed shortcircuit for said second relay, automatic means comprising said bridged relay for opening said short-circuit upon energization of said bridged relay, and a supervisory signal controlled by said' second relay.

In a telephone system, a cord circuit, a relay bridged across said cord, a second relay, a normally closed short-circuit about said second relay. circuitl means controlled by said bridged relay :tor openingsaid shortcircuit, automatic means comprising said second relay for maintaining said short-circuit open, and aV supervisory signal controlled by said second relay.

87. In a telephone system, a plurality of subscribers lines, magnetos at the substations thereon, a cord circuit adapted to be connected with saidl lines, a plug for said cord having a pair of talking contacts and a third contact, a relay connected to said third contact, a normally closed short-circuit about said relay, a second relay. bridged across said cord forcontrolling said shorti circuit, automat-ic means comprising said first-mentioned relay for maintaining said short-circuit open when said first-mentioned relay is energized, and a supervisory signal controlled by said first-mentioned relay.

3S. A telephone system including magneto.

controlling said signal by reversing the current vupon the lineA when connection-is established with an automatic line.

39. A telephone system includingmanual and automatic lines, a cord circuit for use in extending a connection from a manual to an automatic line, a supervisory signal in said cord circuit, and electrically operated means for controlling said signal by reversing the current upon the line when a called automatic subscriber answers.

l0. A. telephone system including automatic subscribers lines, a cord circuit for use in extending a connection to said lines,

a relay bridged across said cord, automatic electrically controlled means for reversing the current through said relay when the called subscriber answers, and a supervisoryT signal controlled by said relay.

el. In a telephone' system, local battery and common battery manual lines and automatic lines, cut-oli' relays associated with .said manual lilies, a cord circuit for use in establishing a connection between any two of said lines, a supervisory relay in said cord, a supervisory signal controlled by said relay, electrically controlled means comprising said supervisory relay dependent for its operation when connection is made with a manual line, upon theI resistance of saidcut-ofl'` relay, a second relay in said cord, a second signal controlled b v said second relay, and means whereby the operation of said second relay is dependent upon a reversal of current upon the line'when connection is made with an automatic line.

42. In a telephone system, a cord circuit, a double-wound polarized relay normally bridged across said cord circuit, a second relay proyided with means for including a battery in the bridge between the windings of said polarized relay.l and circuit means and a battery for energizing said second relay when a plug of the cord is inserted into a jack. A

` 3. In a telephone system, a subscribers line terminating in a jack. a cord circuit adapted to be connected with said line. a double-wound relay normally connected di'- rectly in bridge of said 4cord circuit, a second relay, means for energizing said second relay when connection is made between said cord and jack, and circuit means controlled by the energization of saidsecond relay for connecting a battery in the bridge between the windings of said double-wound relay.

il. In a telephone system. 'a subscribers lineterminating in a jack, a cut-off relay connected with a contact of said jack, a cord circuit having a plug'adapted to be connected with said jack, a double-wound polarized relay connected vin bridge of said cord, a second relay. circuit means for connecting said second relay in series with said cut-ofi' relay when said plug is inserted in said jack, circuit means controlled byfthe energization of said second relay for including a battery between the windings of said polarized relay and in bridge of the cord circuit. and a supervisorysignal controlled by said relays.

cuit.

45. In a telephone system, a subscribers .line, a cut-off relay associated with said line,

a cord circuit, a relay bridged across said cord circuit. a second relay normally shortcircuited through the springs ot' said firstinentioned relay, circuit'means for energizing said second relay in series with said cut.- oil" relay, circuit means controlled by said second relay, when energized, to maintain the short-circuit open, and a supervisory signal controlled by said second relay.

vi6. In a telephone system, common battery and local battery subscribers lines, cutolt relays of diiierent resistances associated with the dilterent types of lines, a cord circuit for use in establishing connection between any two ot said lines, a relay connected in bridge of said cord-circuit, a second relay having a pair of energizing windings, a normally closed short-circuit about one of said energizing windings, circuit means for including the other ot'said energizing windings in series with one of said relays when connection is made between the cord and the line, said second relay dependent for its 0p- 90 eration upon the resistance of said cut-oft relay, and circuit means controlled by t-he energization of said second relay for including a battery in series with said first-mentioned relay in bridge of the cord.

l.- In a telephone system, automatic and manual subscribers lines, trunking means for establishing a talking circuit between any two of said lilies, a supervisory signal for supervising said connection, a battery adapted to be connected with said talking circuit. and automatic means for controlling said supervisory signal by reversing the connection of said battery to said talking cir- 43. In a telephone system. a plurality of automatic 'and manual subscribers lines, trunking means for establishing a talking circuit between any two of said lines. a batcircuit between any two ot said subscribers lines. a supervisory signal for supervising 'said connection. a battery adapted to be bridged across said talking circuit, electrically;controlled means for reversing the connection of said battery with said talking circuit upon the response of the called subscriber. and automatic means for controlling said supervisory signal'by said reversal of current.

50. Inra telephone system, a plurality of automaticv and manual subscribers lines, 130

trunking means including a cord circuit for .establishing a talking circuit between any two of said lines, a supervisory signal in said cord circuit, a battery adapted to be connected with said talking circuit, and automatic .means for reversing the Connection of z tWo of said lines, a supervisory signal in said cord, a battery adapted to be connected with said talking circuit. automatic means for reversing the connection of said battery with Said talking circuit upon the response of the called subscriber, and automatic means for controlling the supervisory signal upon said p reversal of current. A Y

52. In a telephone system, a plurality of automatic and vmanual subscribers. lines, a cord circuit, an automatic switch for finding a. called subscribers line, trunking means for establishing a connection between said cord and said automatic switch,a supervisory sigi nal in said cord, and automatic means in said switch for producing a reversal of current for controlling said supervisory signal.

In a telephone system, a plurality of automatic and manual subscribers lines, a cord circuit, an automatic switch for nding a called subscribers line, a supervisory signal in said cord, a battery normally bridged across the talk-ing conductors in said switch` automatic means -for,reversing the connec tion of saidba-ttery with said conductors, and automatic means for controlling said supervisory signal by said reversal of cur rent.

automatic and manual lines, trunking means for establishing a talking connectionbetween Copies of this patent may be obtained for 54. In Ia telephone system, a plurality of any two of said lines, said means including a cord circuit for extending a connection from a calling subscribers line, electrically controlled means including an automatic switch for extending a connection from said cord to the called line, a supervisory signal in said cord, a battery normally bridged across the talking conductors insaid switch, a relay for controlling said connection, circuit means and a battery for energizing said relay upon the response of the called subscriber, automatic means controlled by the energization of said relay for reversing the connection of said battery with the talking conductors, and automatic means for controlling said supervisory signal by said reversal of current.

55. In a telephone system, local battery manual lines, common batteriv manual lines and automatic lines, a cord circuit for use in establishing connection between any two of.

said lines, a supervisory signal in said cord, and electrically controlled means for operating said signal by different kinds of current. depending upon the line with which said cord isconnected.

56. In a telephone system. local battery manual lines, common battery manual lines and automatic lines, a cord circuit for use in establishing connection between any two of said lines, a supervisory signal in said cord, and electrically controlled means for operating said signal by a,mo1nentar v impulse of alternating current, or from a common direct current source, or by a reversal of current, depending upon the line with which saidy cord is connected.

Signed by me at Chicago, Cook county, Illinois, this 12th day of Sept., 1911.

BERNARD D. IVILLIS.

lVitnesses:

JENME Nonni',

E. H. CLEGG.

five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

